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| Titel |
The spring 2011 final stratospheric warming above Eureka: anomalous dynamics and chemistry |
| VerfasserIn |
C. Adams, K. Strong, X. Zhao, A. E. Bourassa, W. H. Daffer, D. Degenstein, J. R. Drummond, E. E. Farahani, A. Fraser, N. D. Lloyd, G. L. Manney, C. A. McLinden, M. Rex, C. Roth, S. E. Strahan, K. A. Walker, I. Wohltmann |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 2 ; Nr. 13, no. 2 (2013-01-17), S.611-624 |
| Datensatznummer |
250017591
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| Publikation (Nr.) |
 copernicus.org/acp-13-611-2013.pdf |
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| Zusammenfassung |
| In spring 2011, the Arctic polar vortex was stronger than in any other year
on record. As the polar vortex started to break up in April, ozone and
NO2 columns were measured with UV-visible spectrometers above the Polar
Environment Atmospheric Research Laboratory (PEARL) in Eureka, Canada
(80.05° N, 86.42° W) using the differential optical
absorption spectroscopy (DOAS) technique. These ground-based column
measurements were complemented by Ozone Monitoring Instrument (OMI) and
Optical Spectrograph and Infra-Red Imager System (OSIRIS) satellite
measurements, Global Modeling Initiative (GMI) simulations, and
meteorological quantities. On 8 April 2011, NO2 columns above PEARL
from the DOAS, OMI, and GMI datasets were approximately twice as large as in
previous years. On this day, temperatures and ozone volume mixing ratios
above Eureka were high, suggesting enhanced chemical production of NO2
from NO. Additionally, GMI NOx (NO + NO2) and N2O fields
suggest that downward transport along the vortex edge and horizontal
transport from lower latitudes also contributed to the enhanced NO2.
The anticyclone that transported lower-latitude NOx above PEARL became
frozen-in and persisted in dynamical and GMI N2O fields until the end
of the measurement period on 31 May 2011. Ozone isolated within this
frozen-in anticyclone (FrIAC) in the middle stratosphere was lost due to
reactions with the enhanced NOx. Below the FrIAC (from the tropopause
to 700 K), NOx driven ozone loss above Eureka was larger than in
previous years, according to GMI monthly average ozone loss rates. Using the
passive tracer technique, with passive ozone profiles from the Lagrangian
Chemistry and Transport Model, ATLAS, ozone losses since 1 December 2010
were calculated at 600 K. In the air mass that was above Eureka on 20 May
2011, ozone losses reached 4.2 parts per million by volume (ppmv) (58%)
and 4.4 ppmv (61%), when calculated using GMI and OSIRIS ozone profiles,
respectively. This gas-phase ozone loss led to a more rapid decrease in
ozone column amounts above Eureka in April/May 2011 compared with previous
years. Ground-based, OMI, and GMI ozone total columns all decreased by more
than 100 DU from 15 April to 20 May. Two lows in the ozone columns were also
investigated and were attributed to a vortex remnant passing above Eureka at
~500 K on 12/13 May and an ozone mini-hole on 22/23 May. |
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